It is a goal to provide large-capacity magnetic disk devices or hard disk drives (HDDs). One way to do this is to provide a greater number of magnetic disks. However, it also a goal to provide narrower or slimmer HDDs. Accordingly, when there are a greater number of magnetic disks, there are also more actuator arms. As a result, the mass of actuators increases. Consequently, the reaction force produced in a top yoke and bottom yoke of a voice coil motor (VCM) by the actuator coils is further increased during reading/writing. This reaction force causes the top yoke and bottom yoke to vibrate, while also causing the device itself to vibrate.
The drawings referred to in this description should be understood as not being drawn to scale except if specifically noted.